Lecture 4

Anatomical structure of vegetative plants organ.

Plan1. Anatomical structure of root.

2. Anatomical structure of stems and rhizomes.3. Anatomical structure of leaves.

Prepare: ass.

Kernychna I. Z.

These These organisms organisms

are are composed of composed of

an an underground underground root system root system and an over and an over

ground ground shoot shoot

system.system.

Monocots and dicots get their names Monocots and dicots get their names because of the number of cotyledons because of the number of cotyledons

present in their seeds. present in their seeds.

Monocots have one seed leaf or Monocots have one seed leaf or cotyledon while dicots have 2 seed cotyledon while dicots have 2 seed

leaves or cotyledons.leaves or cotyledons.BEAN seed is a dicot and BEAN seed is a dicot and

a CORN seed is a monocota CORN seed is a monocot

There are There are quite a few quite a few differences differences between a between a monocot monocot

and a dicot and a dicot plant. This plant. This table their table their differencesdifferences

::

ROOT

In vascular plants, the root is the organ of a plant body that typically lies below the surface of the soil.Functions of roots are 1.) absorption of water and inorganic nutrients, 2.) anchoring the plant body to the ground, 3) often function in storage of food

Roots of many plants use in medicine:Roots of many plants use in medicine:

Cichorium intydus, of althea (Althea officinalis ),

dandelion (Taraxacum officinale)

Long-section of root has 3 zone:

І. ZONES OF CELL DIVISION with root cap

ІІ. Ellongation;

ІІІ. Differentiation

Or Maturation.

Dermal tissue- such Dermal tissue- such as epidermis that as epidermis that protects the plant.protects the plant.

Ground tissue- Ground tissue- tissue found tissue found between the between the dermal and dermal and vascular tissue. vascular tissue. Serves as Serves as structural strength.structural strength.

Vascular Vascular tissue- tissue that tissue- tissue that transports transports material. Xylem material. Xylem transports water transports water and phloem and phloem transports food.transports food.

Primary structure or root

(in cross sections of differentiation)

1)Epidermis with roots hair

2) Cortex (parenchyma, endodermis with Casparian strip)

3) Vascular cylinder (pericycle, xylem and phloem forms radial bundle)

Monocot roots

vascular bundle

is polyarch, closed,

and radial.

In dicot roots

with primary

structure

vascular bundle

is closed, radial,

and tetraarch.

In dicot roots, the xylem In dicot roots, the xylem tissue appears like a 3-tissue appears like a 3-

pronged or 4-pronged star pronged or 4-pronged star

Dicot roots with secondary vascular bundle structure have opened collateral vascular bundles in stele, which are arranged in circle. Between them there are wide medullary rays which are start in primary xylem and are situated in the center of a root. Dicot roots with secondary nonbundle structure have solid ring of vascular cambium, solid zone of phloem above it and solid zone of xylem below cambium. In the center there is primary xylem. Primary medullary rays stretch from it, Secondary rays are formed by cambium.

In medicine use herbs many plants (stems with leaf, flowers).

In most plants stems are located above the soil

At some woody plants use in medicine

(snowball tree, oak-tree )

primary bark (cortex)

Monocot Stem.

A cross section : 1) epidermis;

2)  cortex (chlorenchyma and sclerenchyma);

3) Vascular cylinder (scattered vascular bundle is closed collateral.).

Monocot stems differ from dicot Monocot stems differ from dicot stems in that they lack secondary stems in that they lack secondary growth growth

No vascular cambium nor cork No vascular cambium nor cork cambium cambium

Stems usually uniform in diameter Stems usually uniform in diameter Scattered vascular bundles (not in Scattered vascular bundles (not in

a ring like dicot stems) a ring like dicot stems)

DICOT STEM:1) Open collateral vascular bundle; 2) Under epidermis is collenchim,

not sclerencim

A. A. epidermis (outermost layer of cells epidermis (outermost layer of cells forming the initial covering on a forming the initial covering on a stemstem). ).

B. B. cortex (ground tissue that surrounds cortex (ground tissue that surrounds the vascular cylinder or stele). the vascular cylinder or stele).

C. C. endodermis with Casparian strip endodermis with Casparian strip (regulates the flow of water and (regulates the flow of water and dissolved substances). dissolved substances).

D.D. primary xylem (water-conducting primary xylem (water-conducting tissue found in the vascular cylinder or tissue found in the vascular cylinder or stele) stele)

E.E. primary phloem (food-conducting primary phloem (food-conducting tissue found in the vascular cylinder or tissue found in the vascular cylinder or stele) stele)

WOODY STEM:1) The "bark" of the tree consists of the periderm + the phloem ; 2) The vascular cambium cells divide to produce secondary xylem to the inside and secondary phloem to the outside

1)Has 1)Has tracheidstracheids in their in their xylemxylem

2)2)GymnospGymnospermerm wood wood also often also often contains contains

resinresin ductsducts

Gymnosperm stems

A RHIZOME is underground modification of stem, which is formed at

perennially herbacеous plants for an accumulation nutritives and vegetative reproduction.

Has the well formed stocking parenchyma; mechanical and vascular tissues are expressed poorly. In medicine use

rhizome of sedge cane, fern, valerian and other

Leaf– lateral vegetative organ of plants, the general function its are photosynthesis, transpiration.

There are several types of leaves: 1) Bifacial)2) Izolateral ;3) Radial )

LEAF CROSS SECTIONLEAF CROSS SECTIONDermal Tissue:Dermal Tissue: outer outer

single cell layer protective single cell layer protective tissue. tissue.

Cuticle:Cuticle: layer of waterproof layer of waterproof wax on the outer surface of wax on the outer surface of

the dermal tissue. the dermal tissue. Ground Tissue:Ground Tissue: usually two usually two

layers, closely packed layers, closely packed upper layer and loose upper layer and loose

lower layer – lower layer – photosynthetic tissue. photosynthetic tissue.

Air SpacesAir Spaces: rapid diffusion : rapid diffusion of carbon dioxide to the of carbon dioxide to the cells for photosynthesis. cells for photosynthesis. Guard Cells:Guard Cells: control the control the

closing and opening of the closing and opening of the stomatal pore. stomatal pore.

Stomata:Stomata: rapid entry of rapid entry of carbon dioxide into the leaf carbon dioxide into the leaf

from the air.from the air.

bifacial (common for dicot)

isolateral (common for

monocot and dicot plants)

Radial (common for gymnosperm)